Home
Class 11
PHYSICS
The tungsten filament of an electric lam...

The tungsten filament of an electric lamp has a surface areaA and a power rating P. If the emissivity of the filament is `varepsilon` and `sigma` is Stefan's constant,the steady temperature of the filament will be:

A

`T=((P)/(A epsilon sigma))^4`

B

`T=((P)/(A epsilon sigma))`

C

`T=((A epsilon sigma)/(P))^(1//4)`

D

`T=((P)/(A epsilon sigma))^(1/4)`

Text Solution

Verified by Experts

The correct Answer is:
D
Rate of energy (Power) `P=A epsilon sigma T^4`
`T=((P)/(A epsilon sigma))^(1/4)`
Promotional Banner

Similar Questions

Explore conceptually related problems

The filament of an electric bulb is made of tungsten.

The tungsten filamet of an electric lamp, has a length of 0.25 m and a diameter of 6xx10^(-5) m. The power rating of the filament is 0.8, estimate the steady temperature of filament. Stefan's constant =5.67xx10^(-8) W//m^(-2)//K^(4) .

To support tungsten filament in electric bulb, the steel used is

A 100W bulb has tungsten filament of total length 1.0m and raidius 4xx10^(-5)m . The emiswsivity of the filament is 0.8 and sigma=6.0xx10^(-8)Wm^(-2)K^(-4) . Calculate the temperature of the filament when the bulb is oprating at correct wattage.

The tungsten filament of an electric lamp has a length of 0.5m and a diameter 6xx10^(-5)m . The power rating of the lamp is 60 W . Assuming the radiation from the filament is equivalent to 80 % that of a perfect black body radiator at the same temperature, estimate the steady temperature of the filament.(Stefan constant =5.7xx10^(-8)Wm^(-2)K^(-4) )

A bulb made of tungsten filament of surfece area 0.5 cm^2 is heated to a temperature 3000K when operated at 220V.The emissivity of the filament is in=0.35 and take sigma=5.7xx10^-8 mks units. Then the power of the bulb is,

The tungsten filaments of two electric bulbs are of the same length. If one of them gives 25 W power and the other 60 W power, then

Knowledge Check

  • A electric bulb has a filament made of?

    A
    Iron
    B
    Lead
    C
    Copper
    D
    Tungsten

  • To support tungsten filament in electric bulb, the steel used is

    A
    `Cr`
    B
    `Ni`
    C
    `M`
    D
    `Mo`

  • The surface temperature of the sun is about 6000 K. the sun's radiation has maximum energy at a wavelength of 0.5 mu m. a certain light bulb filament emits radiations with a maximum at 2 mu m. if both the surface of the sun and the filament have the same emissive characteristics, then the temperature of the filament will be

    A
    1500 K
    B
    2000 K
    C
    2500 K
    D
    3000 K